In electronically controlled engine systems, a parameter which is often needed for computation purposes in the control systems computer is the barometric pressure. A common way to sense the barometric pressure would be to purchase a sensor dedicated for the purpose of reading barometric pressure. This is a rather expensive means to obtain the desired result. It complicates the system design with additional wiring and expense, as well as tying up the use of an additional input channel to the computer.
The subject disclosure provides a technique to read barometric pressure utilizing an existing sensor employed for the purpose of reading manifold absolute pressure (MAP). The sensor works in tandem with the electronic control system's computer and an inexpensive solenoid to provide the electronic control system both with MAP reading and with barometric pressure readings to keep the engine running smoothly.
It is, therefore, an object of this invention to utilize a single MAP sensor to measure barometric pressure and to measure MAP.